solar panel install + power measurement as production or consumption

[mqu]

hello all,

I have an PZEM-004T connected to ESP32 ; all works fine, but, now, I would like to make "negative" power measurement when my solar panel produce some electricity to the grid.

Now, what I have is the absolute value of the power. Actual software is unable to distinguish production to consumption.

Do you have some advice ?

[vortigont]

That's a tricky question. If you measure AC current actually there is no way to tell in which direction the energy "flows". It might be possible to set a DC meter (i.e. PZEM003 model) right after the solar panel and a an AC ones for inverter / grid line / house than do some tricky math equalizing all of it.
I was trying to set a 3 phase line monitoring with PZEMs - it work more or less fine for single phase loads but gives weird results if using some pure 3-phase load with no neutral connection :)

[mqu]

some information about flow and AC measurement : https://www.eevblog.com/forum/projects/how-to-measure-the-direction-of-a-c-power-flow/

[vortigont]

Also found this https://github.com/apreb/eNode. Looks like with some hardware mod an older PZEMs are capable of detecting energy flow direction. You might still find some of those on aliexpress
But new ones (PZEM004v30) does not have this pin. I've run through the datasheet - those new pzems are based on quite a good chip that is capable of doing lot's of features including energy accounting debit/credit. But it's all hidden behind PeaceFair firmware with cumulative energy counter only